ESP8266 - Button - Servo Motor

This tutorial instructs you how to use an ESP8266 and a button to control a servo motor. In detail:

The above process is repeated over and over again.

The tutorial has two sections:

Hardware Preparation

1×ESP8266 NodeMCU
1×Micro USB Cable
1×Push Button
1×(Optional) Panel-mount Push Button
1×Servo Motor
1×Breadboard
1×Jumper Wires
1×(Optional) 5V Power Adapter for ESP8266
1×(Optional) ESP8266 Screw Terminal Adapter

Or you can buy the following sensor kit:

1×DIYables Sensor Kit 30 types, 69 units
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Overview of Servo Motor and Button

If you are unfamiliar with servo motors and buttons (including pinouts, how they work, and how to program them), the following tutorials can help:

Wiring Diagram

The wiring diagram between ESP8266 NodeMCU and Button Servo Motor

This image is created using Fritzing. Click to enlarge image

See more in ESP8266's pinout and how to supply power to the ESP8266 and other components.

Please note that the wiring diagram shown above is only suitable for a servo motor with low torque. In case the motor vibrates instead of rotating, an external power source must be utilized to provide more power for the servo motor. The below demonstrates the wiring diagram with an external power source for servo motor.

The wiring diagram between ESP8266 NodeMCU and servo motor external power supply

This image is created using Fritzing. Click to enlarge image

Please do not forget to connect GND of the external power to GND of ESP8266.

ESP8266 Code - Button Controls Servo Motor Without Debouncing

/* * This ESP8266 NodeMCU code was developed by newbiely.com * * This ESP8266 NodeMCU code is made available for public use without any restriction * * For comprehensive instructions and wiring diagrams, please visit: * https://newbiely.com/tutorials/esp8266/esp8266-button-servo-motor */ #include <Servo.h> #define BUTTON_PIN D1 // The ESP8266 pin connected to button's pin #define SERVO_PIN D5 // The ESP8266 pin connected to servo motor's pin Servo servo; // create servo object to control a servo int angle = 0; // The current angle of servo motor int prev_button_state; // The previous state of button int button_state; // The current state of button void setup() { Serial.begin(9600); // Initialize the Serial to communicate with the Serial Monitor. pinMode(BUTTON_PIN, INPUT_PULLUP); // Configure the ESP8266 pin to the input pull-up mode servo.attach(SERVO_PIN); // attaches the servo on pin 9 to the servo object servo.write(angle); button_state = digitalRead(BUTTON_PIN); } void loop() { prev_button_state = button_state; // save the last state button_state = digitalRead(BUTTON_PIN); // read new state if(prev_button_state == HIGH && button_state == LOW) { Serial.println("The button is pressed"); // change angle of servo motor if(angle == 0) angle = 90; else if(angle == 90) angle = 0; // rotate the servo motor to the angle position servo.write(angle); } }

Detailed Instructions

To get started with ESP8266 on Arduino IDE, follow these steps:

  • Check out the how to setup environment for ESP8266 on Arduino IDE tutorial if this is your first time using ESP8266.
  • Wire the components as shown in the diagram.
  • Connect the ESP8266 board to your computer using a USB cable.
  • Connect the ESP8266 NodeMCU to the computer using a USB cable.
  • Open Arduino IDE on your computer.
  • Choose the correct ESP8266 board, such as (e.g. NodeMCU 1.0 (ESP-12E Module)), and its respective COM port.
  • Copy the above code and open it in the Arduino IDE.
  • Click the Upload button in the Arduino IDE to compile and upload the code to the ESP8266.
  • Press the button multiple times.
  • Check out the changes in the servo motor.

※ NOTE THAT:

In practice, the code mentioned above does not always work correctly. To ensure it functions properly, we need to debounce for the button. Debouncing the button can be difficult for those new to ESP8266. Fortunately, the ezButton library makes this process much simpler.

ESP8266 Code - Button Controls Servo Motor With Debouncing

Why is debouncing necessary?. See ESP8266 - Button Debounce tutorial for more information.

/* * This ESP8266 NodeMCU code was developed by newbiely.com * * This ESP8266 NodeMCU code is made available for public use without any restriction * * For comprehensive instructions and wiring diagrams, please visit: * https://newbiely.com/tutorials/esp8266/esp8266-button-servo-motor */ #include <Servo.h> #include <ezButton.h> #define BUTTON_PIN D1 // The ESP8266 pin connected to button's pin #define SERVO_PIN D5 // The ESP8266 pin connected to servo motor's pin ezButton button(BUTTON_PIN); // create ezButton object for pin 7; Servo servo; // create servo object to control a servo int angle = 0; // The current angle of servo motor void setup() { Serial.begin(9600); // Initialize the Serial to communicate with the Serial Monitor. button.setDebounceTime(50); // set debounce time to 50 milliseconds servo.attach(SERVO_PIN); // attaches the servo on pin 9 to the servo object servo.write(angle); } void loop() { button.loop(); // MUST call the loop() function first if (button.isPressed()) { // change angle of servo motor if (angle == 0) angle = 90; else if (angle == 90) angle = 0; // rotate the servo motor to the angle position Serial.print("The button is pressed => rotate servo to "); Serial.print(angle); Serial.println("°"); servo.write(angle); } }

Detailed Instructions

  • Install the ezButton library. Refer to How To for instructions.
  • Copy the above code and open it in the Arduino IDE.
  • Click the Upload button in the Arduino IDE to upload the code to the ESP8266.
  • Push the button multiple times.
  • Check out the changes in the servo motor.

Video Tutorial